PacifiCorp 2007 Integrated Resource Plan (May 30, 2007)

PacifiCorp – 2007 IRPChapter 7 – Modeling and2016 Resource Capacity Mix, with Preferred Portfolio Resources($8 CO2 Adder Case)Gas-CHP0.7%Gas-SCCT2.8%Interruptible2.2%Hydroelectric10.0%Renewable2.9%Class-1 DSM1.9%Gas-CCCT21.8%Pulverized Coal50.5%Existing Purchases4.2%Front Office Transactions3.0%FORECASTED FOSSIL FUEL GENERATOR HEAT RATE TRENDPursuant to the Utah Public Service Commission’s order on the PURPA Fuel Sources Standard(Docket no. 06-999-03), this section reports the forecasted average heat rate trend for the company’sfossil fuel generator fleet on an annual basis, accounting for new IRP resources and currentplanned retirements of existing resources. The fleet-wide heat rate represents the individualgenerator heat rates weighted by their annual generation. (Note that system dispatch accounts foran $8/ton CO 2 cost adder). For existing fossil fuel resources, four-year average historical heatrate curves are used, whereas new resources use expected heat rates accounting for degradationover time.Figure 7.34 shows the fleet weighted-average fossil fuel generator heat rate trend from 2007through 2026, indicating the contributions from existing coal resources, existing gas resources,new coal resources, and new gas resources (including CHP). The average heat rate declines from10,255 to 9,082 Btu/kWh, a compounded average annual decrease of 0.6 percent. As indicated inFigure 7.34, the heat rate contribution of existing coal plants drops significantly, declining from91 percent of the system total in 2007 to only 53 percent by 2026. Also underlying the trend isincreasing reliance on generation from new gas and wind resources, the later displacing generationfrom existing coal plants.209